Some days work kicks your ass. You're not blocked, but you can't find a rhythm and that means you're just plodding along, working around problems instead of through them. And nothing ever seems to get any closer despite how much time you've already put in.
At 7:30 pm you tell your editor that though you were shooting for today, you want some extra time to make it spiffy for tomorrow and solve a few little hurdles. You go off for a bit, enjoying some recreation and Curb Your Enthusiasm. Then you get back to work.
At 1am, you tell your editor that the whole thing has started to unravel. You're not asking for help, you're just letting him know that as close as you thought you were, you may as well start from page 1.
You break it down on paper. Find the essentials, arrange in rough order. See if anything crops up with distractions limited. Then you find an empty breakdown doc template and fire it up. You do the same thing here, with more emphasis on structure. You're getting warm.
Finally, at 1:37 am you finish typing. You've still got one major, gigantic gaping flaw in your story, but you're feeling much better. The story has returned (along with your mojo), and you tell your editor a minute later that all is right with the world. Because sometimes all you need is a sounding board or someone to vent to, and you don't get no lip at 1:30 in the morning.
That was basically my day, with a lot more editing thrown in the mix early. And to think, if at any point I had stopped, I might not be a couple hours work from getting this treatment revised, sent off, and a miniseries in production.
Moral: Even when it feels like you're not making any progress or doing terrible work, push through. Keep pushing until you get a breakthrough, because it's bound to come at some point, when you simplify or make things complex. It's out there, waiting for you to find it.
Say, don't I have a screenplay that could use that same sage advice...?